Enhanced coherence by coupling spins through a delocalized π-system: Vanadyl porphyrin dimers
Iago Pozo, Zhijie Huang, Federico Lombardi, Dimitris Alexandropoulos, Fanmiao Kong, Michael Slota, Igor Tkach, Marina Bennati, Jie‐Ren Deng, Wojciech Stawski, Peter N. Horton, Simon J. Coles, William K. Myers, Lapo Bogani, Harry L. Anderson
Abstract
Vanadium(IV) magnetic centers are prime candidates for molecular quantum units. One long-standing question is how to obtain a scaffold that connects multiple centers and allows two communication modalities: magnetic and electronic. We have synthesized and studied a selection of vanadyl porphyrin dimers as models of the most synthetically accessible linear porphyrin arrays. We show that a strongly π-conjugated backbone places the magnetic system in an intermediate regime dominated by exchange coupling ( J ) and protects the quantum coherence against electron pair flip-flop processes at low temperatures (<10 K). This result is a fundamental step toward the design of molecular materials for single-molecule devices controlled by microwaves with electrical readout.